On June 10, MidTown Corporation sold typewriters to FirstRate Grocery Store on credit for $5,000. FirstRate signed a financing statement containing the names and addresses of the parties and describing the typewriters as collateral. MidTown filed the financing statement on June 21. Select one or more: a. MidTown need not sign the financing statement to perfect its security interest in the collateral. b. MidTown must sign the financing statement in order to perfect its security interest. c. MidTown had a perfected security interest in the collateral even if it had not filed the financing statement. d. MidTown had a perfected security interest in the collateral even if it had not filed the financing statement